Tablesaw coving technique

[MarkG]

Any of you woodworkers----I've read about (and maybe even tried once years ago) a technique involving clamping an angle fence across the saw blade and taking very small bites feeding the stock across at an angle to create a 'cove', raising the blade a bit between each pass.

I want to try this in HDPE for a job coming up and wondered how it machines in comparison to wood? My first thought is that it should cut like butter, so hopefully, I can create the coves I need using this technique! I know you can't take very big bites and know this isn't ideal, but I don't have a shaper and am not about to job this out.

Thanks!

 

[gasgas17]

I have done it with wood a few times, but no HPDE. I would recommend using a finger board or 2 to ensure its not moving around on you. As well as a blade lubricant to help prevent the plastic from sticking to the blade. How thick is the stock your using?

 

[readhead]

I have done it to make wood gutters on a restoration project. Took a few times to get it right but worked pretty well. I used a rip blade to hog out material and finished with a fine blade. A little sanding and was all done.

 

[Toolfool]

Done it many times with wood and MDF. Best way is to clamp 2 parallel fences that you can run your material between. I would imagine the HDPE would gum up the blade pretty quickly at table saw RPM's.

 

[galute]

I don't know what coving is? But I can help with the lube. We cut HDPE a lot with chain saws and just fill the oiler with dishwashing liquid. Works great and no gumming up.

 

[kkroger]

Done it when I was a Sophomore in High School on a Rockwell Tablesaw took 3 passes to get the depth I wanted. Featherboard and Paddles!

 

[McFarmer]

I tilt the blade to get a different profile. Tilt towards the work of course.

Use different diameter blades, 8 inch blade will make a small radius curve.

Use a board in either side of the work, make a push block that fits nicely between them and a cleat in the back you can push right through the cut.

Never done anything but solid wood.

 

[Divcod]

Used a dado set up to duplicate siding on a 80 year old chicken coup. Actually went full depth on one pass and would think plastic would be about the same. Depth of cut maybe a function of the saw horse power, good luck.

 

[bullnerd]

I think your thinking correctly.

I've machined a lot of it, I've table sawed it to size, but don't really remember it being anything to remember. It was a long time ago.

Usually static cling is worse on plastic than it gumming up. The chips cling to everything.

 

[brianh]

HDPE machines fine no need for lube, I use it for making jigs it routs and cuts just fine.

 

[racingtadpole]

HDPE machines fine no need for lube, I use it for making jigs it routs and cuts just fine.

^^^ This.

I cut and shaped a heap of it with a compound saw and a router about six months ago, the only really issue I had was it choked the dust extractor attachment on the back of the saw a couple of times.

 

[mbatarga]

As above comments - but also use carbide saw blade of course.

 

[whateg01]

I tilt the blade to get a different profile. Tilt towards the work of course.

Use different diameter blades, 8 inch blade will make a small radius curve.

Use a board in either side of the work, make a push block that fits nicely between them and a cleat in the back you can push right through the cut.

Never done anything but solid wood.

Angling the fence will also yield a smaller radius, though it isn't really a radius since it isn't constant.

 

[whateg01]

The only real concern I have about this is that it can be difficult to "get a grip" on HDPE. So, make sure you are using push sticks and fingerboards. And be prepared for it to slip if you don't have a good hold on it.

 

[dutchgray]

The only real concern I have about this is that it can be difficult to "get a grip" on HDPE. So, make sure you are using push sticks and fingerboards. And be prepared for it to slip if you don't have a good hold on it.

I think I would be making the angle fixture so the work piece can only move forward or backward and then just push it though with a stick